METHOD FOR THE RACEMISATION OF ENANTIOMERS OF .ALPHA.-LIPOICACID

摘要

Method for the racemisation of pure optical isomers of .alpha.- lipoic acid or mixtures of pure optical isomers of .alpha.-lipoic acid, wherein one of the optical isomers is present in excess. The .alpha.-lipoic acid is racemised in solid form, in suspension, or in a mixture of inert organic solvents with or without addition of water at temperatures of between 110.degree.C and 200 .degree.C at pressures of from normal pressure up to 50 bar for 10 to 48 hours. The yields are approximately 70% with a racemised proportion of an enantioner of up to 49%.